Due to growing traffic demands and frequent lane closures, long traffic queues and delays are very common. As result of lane closures due to work zone or traffic incidents, queues can build quickly and often grow past advanced static warning signs, especially during rush hour traffic. In such situations, many drivers catch the back of the queue by surprise increasing the probability of rear end collisions. An important measure to counter such rear-end collisions is to provide advanced safety messages to the drivers of the vehicles that are approaching the back of the queue. A number of research studies and field experiments have estimated that an advanced warning can help prevent rear-end collisions by 20-90%. In addition to avoiding rear-end collisions, advanced warning messages can guide drivers approaching the end of the queue to take an alternative route, which in turn helps lower the congestion and thereby improve traffic mobility.
Many traffic information systems are being developed using a variety of wireless technologies e.g., cellular, Bluetooth, and radio frequency identification, to estimate traffic parameters and warn drivers in a timely manner. However, all these traffic information systems require special roadside infrastructure support and depend on a third party cellular infrastructure to acquire, process and disseminate traffic data. Furthermore, such systems gather traffic data only where infrastructure support is available and usually these traffic data updates are quite infrequent.